jcrow

I notice Jenny Doan rarely sets her seams. Maybe once in five YouTube videos she'll set one seam. I set my seams all the time. The threads seem to bury themselves deep into the fabric when I set the seams. I like when they do that. That is why I set my seams.

Intrepid Niddering

I'd been wondering this, too, and am surprised to find it's done to make the pieces lie flatter. I guess I'm doing it wrong because when I don't set my seam, my seam allowance stays open and flat, but if I set it, the seam allowance likes to close back together.

Yakkity

Clapper is available through Amazon. I recently purchased one.

caroloto

Set the seams...this what I have noticed, when I use 100% cotton thread pressing seem to shrink the thread. If the thread isn't 100% cotton or another type of thread I see no difference whether I press during or after the block or even the whole top is done.

I have noticed if I don't press my seams line up and points far better then when I iron (yes I'm pressing/blocking) before hand. One of the classes I took a few years back by one of the top teachers, has plenty of books and patterns out told us we didn't need to iron as much and would find it easier to match seams.